The present invention relates to lighting fixtures for industrial applications, and more particularly to a lighting fixture which is easily and safely accessed for servicing and repairs.
In industrial applications such as mining, processing plants or refineries, there are typically long runs of piping or conveyors from one building structure to another. Often there are elevated catwalks along these long runs for maintenance purposes. Lighting fixtures are typically mounted on the catwalks to provide illumination in dark areas and at night.
Typical methods for servicing or replacing components of such lighting fixtures involve use of a ladder to access the lighting fixture head, which is often supported more than eight to ten feet above the catwalk. Obviously, a danger exists for the maintenance worker precariously climbing a ladder supported on a catwalk high above the ground.
One known method for providing access to the light fixture head without use of a ladder is by incorporating a light fixture pole with a means to permit a top portion of the pole to pivot downward. For example, U.S. Pat. No. 6,957,832 to Pannekoek discloses a light fixture pole having an interconnect joint disposed at a forty-five degree angle to permit a top portion of the pole to pivot with respect to the bottom portion, thereby allowing a maintenance worker to access the lighting fixture head.
However, one problem with the disclosed pivot joint is that its geometry causes the lighting fixture head to be pivoted laterally beyond the catwalk, thereby requiring a maintenance worker to reach outwardly over the rail of the catwalk to access the head. Again, a danger exists for the maintenance worker, who needs to reach over the catwalk rail to access the light fixture head,
Another drawback with conventional lighting fixtures is the number of tools typically required to service or replace components of the fixture. For example, removal of the fixture head from the mounting pole of a conventional lighting fixture may require one or more differently sized wrenches and screwdrivers to loosen and remove fixture hardware, which gives rise to another problem relating to loose hardware. Thus, a maintenance worker would typically need to carry a large tool chest or satchel along the catwalk in order to perform such tasks, and must also be careful not to drop or lose the hardware necessary to mount the lighting fixture head to the pole.
Still another consideration with lighting applications in industrial environments such as mining, processing plants or refineries is the requirement in certain hazardous installations that the lighting fixtures not produce any electrical arcs or sparks. In particular, disconnecting a live plug connection of a light fixture for servicing or repair, for example, could result in an electrical arc or spark, which must be prevented in a hazardous atmosphere for safety reasons.
One approach for addressing this safety issue is to terminate power at the source before disconnecting any lighting fixture wiring or plug connections. The drawback here is that a number of fixtures will typically be turned off at the same time during servicing of a single fixture, resulting in large areas of the facility not illuminated.
Another solution is to provide individual fixtures with on/off switches that must be manually actuated before servicing the fixture. This adds to the cost of the fixture itself, as well as the cost of installation. There also remains the possibility that the maintenance worker inadvertently fails to activate the switch before making any electrical disconnections.
Accordingly, it would be desirable to provide a lighting fixture for mounting on a catwalk that is safely and easily accessible by a maintenance worker standing on the catwalk. It would be further desirable to provide a lighting fixture that can be serviced and repaired without the need for tools and with minimal risk of losing lighting fixture mounting hardware. It is still further desirable to provide a safe lighting fixture that will automatically electrically disconnect upon initiation of servicing or repair.